C-C-Change?
by Her-secret-letters1800
Summary: Alec had been away on multiple demon calls and had decided to stay at the Institute for the time being. When he finally finds a break, he decides to go back and live with Magnus. However, upon entering his apartment, there is an explosion and Alec's relationship with Magnus becomes...complicated. *A short side story
1. Chapter 1

**Hello ALL! New story! I thought I'd write something more peppy and lively. Please read and I hope you all enjoy it!**

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Chapter 1

**Explosion**

The evening sky was crisp orange and the sun was setting onto the skyscrapers of Brooklyn, New York, reflecting off the buildings. It was fairly quiet on the streets and only a few people were still out and Alexander Lightwood was one of them. He was wearing a plane black shirt, warned out jeans and he was making his way down the block towards Magnus's red brick warehouse.

He had not had any free time to be with the warlock because he had been called to so many missions that he decided it would be better if he stayed at the Institute until it was over. Magnus of course had protested, begging him to stay but Alec defended that he was a Shadowhunter and it was his job. The first few nights back in the Institute was alien for Alec. He disliked the empty feeling beside him while he slept and wished Magnus was there. He was used to seeing vibrant wall colors, antique furniture and a table full of makeup. However, the more nights he stayed, Alec became comfortable in his room liking the simplicity of just a bed, desk, one draw and closet, and the dull shading colors on the wall.

Finally though, he had caught a break and Alec had rushed out of the Institute, and in doing so, pushed by his sister who was asking him where he was going and made his way to his second home; the home he preferred to stay in. He was so eager to see Magnus that he wanted to make a surprise visit and had not call Magnus to let him know he was coming.

Upon reaching the warehouse, he made his way through the front door and bounded up the stairs when a sudden explosion sounded through the building. Alec snapped his head up knowing well that only Magnus could send an explosion like that, and he dashed the rest of the way up bursting through Magnus's loft. The fear of it being a demon attack was eased as a cloud of multi-colored smoke floated around the room. The smoke was, however, heavy enough to make his eyes watery and the boy placed his arm over his face.  
"Magnus!" Alec called swiping the spoke away from his face. The origin of the explosion happened in the bedroom and Alec crept over to the room and saw something on the floor that made Alec gasp. The boy rushed over and saw a pile of clothes scattered on the floor and he picked it up with utter disbelief and confusion. For a moment, Alec held his breath. What if Magnus died along with the explosion? But if there was an explosion then his clothes would be gone too. Did he transport to another dimension? What the hell was he doing?  
"Magnus where are you?!" Alec called scrambling to his feet and went from room to room desperately searching for the warlock. Magnus, however, was nowhere to be seen and after a while, Alec slumped down onto the couch in the common room. The Shadowhunter brought his head down on his hands raking through his mind of the possibilities of what could have happened. He wondered if he should notify the Clave, or call Isabelle and the others to investigate. He took a ragged breath as fear began to sink in, his nerves jumping under his skin. A sudden noise from the bedroom pulled him out of his despair and he froze, wondering what the noise could be. He crept back over to Magnus's room and he saw a figure emerge from within the closet and dash across the floor. Alec's eyes widened in surprise and he slowly made his way to the other side of the bed and what he saw, he would have never believed. Alec's legs buckled and he dropped to his knees, placing a hand over his mouth and whispered.  
"Magnus..."

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**Oh, I wonder what happened to Magnus... I hope you all enjoyed it! Please, please review and tell me how you guys liked it! (and you can tell me you're guesses of what happened to Magnus)**


	2. Chapter 2

**Thank you so much for your last reviews! I enjoyed them greatly. Thank you for waiting and here is the next chapter. Enjoy**

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Chapter 2

**Metamorphosis**

"So wait, tell me what happened again?" Isabelle asked pacing around the room her fingers against her temple. She was wearing grey sweat pants, a red tank top and her hair was divided into two separate breads. Alec sat on the couch with his head in his hands. He had called his sister in desperation in the middle of the night because he knew, out of everyone, Isabelle would understand the situation.  
"For the hundred times Izzy, I don't know." Alec hissed running a hand through his hair. He was tired and still trying to process what was going on.

"Run it through me again." She said sitting next to him. "Please," she added softly. Alec took a breath and repeated his story once again.

"I was going up to his apartment when I heard an explosion and when I got there, the whole apartment was in smoke. There were no fire, and the fact that the smoke was colorful meant that Magnus was probably working on… magic stuff. I went to look for him and when I did…" Alec trailed off as a shiver went down his spin. "He was a baby, a naked baby crawling around his bedroom floor."

"That is one hell of story," Isabelle said shaking her head in disbelief. "Do you know what happened?" Alec shook his head.

"A spell went wrong maybe?" He suggested rubbing his own aching temples.

"I want to see him," Isabelle said standing up.

"I didn't know where to put him so he's sleeping on his bed." Alec said going to the bedroom, Isabelle following closely behind. When her eyes went to the baby, it softened. Magnus was wrapped in a soft blue blanket, his little hands curled into a fist and his feet gave little kicks. She bent over and looked down at Magnus.  
"He's so adorable." She whispered. "Can I hold him?" She asked. Alec hesitated.  
"I don't know about that. It seems that the transformation took a lot out of him. After I got him wrapped up, he instantly fell asleep. I don't want to wake him." Alec said. Isabelle stared at her brother with a gapped expression before speaking.  
"Wow, you'll be a great father one day."  
"Yeah well, I didn't expect my first child to be my boyfriend." Alec said with bitter sarcasm.  
"How long do you think this will last?" Isabelle asked lightly brushing her red painted fingernails along Magnus's caramel colored cheeks. He stirred and Isabelle bit her lip from squealing.  
"I don't know, hopefully it'll wear off by the end of the day? Maybe? By the Angels what the hell am I supposed to do?" Alec asked.  
"Well, for starters we're going to have to go shopping."  
"What do you mean?" Isabelle looked at her brother as if he was stupid. She pointed to Magnus.  
"Look at him Alec!" She nearly shouted. Alec brought a hand over her mouth and they waited for Magnus to wake and cry but he only turned his head. They let out sigh of relief and Alec dropped his hand. "He's a baby!" She whispered. "I doubt he'll be changing any time soon." Alec looked down at Magnus with concern and annoyance. "We'll have to buy a crib, dippers, formula, baby food, and clothes, since he won't be fitting his for a while." She said.  
"What the hell did you get yourself into?" Alec whispered.

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**I hope you all enjoyed it! Please review and tell me how it was! PLEASE! :D**


	3. Chapter 3

**Hey guys, thank you for your last reviews! I hope you all enjoy baby Magnus! Anyway, here's the new chapter!**

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Chapter 3

**Parenting**

The next day, Isabelle and Alec went shopping separately. Alec went looking for a crib, a stroller and a few other things that needed to be assembled while Isabelle took Magnus shopping. She found some cute one piece pajamas, like a soft blue pajama with kitten print on it. She bought him daily clothes like a green monkey shirt with cargo pants little vans shoes. Then she went and bought other necessities a baby needs, such as dippers, baby food, and formula.

By the time Isabelle finished, Alec was already back in Magnus' apartment setting up the crib in the bedroom. He had finished assembling the playpen stroller, which was placed before the sofa, where Magnus could stand and play with the toys on the seat. Isabelle sat on the sofa with Magnus and began playing with him, bouncing him on her knee and he laughed, clapping his hands. Once Alec was finished, he stepped out of the bedroom and leaned against the door frame.

"That is my boyfriend you're _googooing_ with." He said crossing his arms over his chest but he had to admit, Magnus was adorable.

"Need I remind you, he is just a baby? Isn't that right Maggie?" She said nuzzling her nose against his. "Yeah," She laughed when he laughed.

"Maggie?" Alec said raising an eyebrow. Isabelle shot her brother a glare.

"Don't judge me, besides he likes the nickname. Don't you?" Alec shook his head and ran a hand through his jet black hair.

"You're having way too much fun with this."

"Alec, why are you being so stubborn about this?"

"B-because this isn't normal! Isabelle, I just spent the last three hours setting up a playpen and a crib, for my _boyfriend_ because he's a _baby_! How would you like me to handle this?"

"Isn't there someone we can go to who might know what to do?"

"The person we usually go to is Magnus!" He said pointing to the baby. "But being as he_ is_ the problem…" he trailed off and threw his hands up in the air in defeat.

"Alright, calm down, so right now, you just have to work with it. Oh, look, you upset Maggie." Isabelle said turning the baby around so that Alec could see and to his surprise, Magnus was, in fact, giving him a pouted look. Alec tilted his head to the side in wonder and walked over and kneeled in front of the baby.

"Can you understand us?" He asked. Magnus darted for the ground as if he saw something interesting but Isabelle kept him on her lap. "Magnus, can you understand us?" Alec urged trying to look into the green-gold cat eyes. Magnus looked into Alec's blue eyes for a while before he stretched his little arms out. Alec give him his hand and there came a weird ringing in the back of Alec's mind.

_I'm here Alec, _came a grown voice.

Tears weld from the baby's eyes and he started crying and Alec stood up in surprise.

"Alec, you upset him!" Isabelle said and tried to calm him, resting him against her shoulder and rocking back and forth, patting his back. Magnus's cries only grew to a wail as he tried to reach for Alec. "Here, take him, he doesn't want me." She said holding Magnus up to him. Alec hesitated before taking the baby and cradling him in his arms. At an instant, Magnus nuzzled himself in Alec's chest and fell asleep. Alec sat down onto the sofa and looked affectionately down at the baby. Isabelle reached out and whipped away a few tears that were still falling.

"Remember those nights when mom and dad had to stayed late for work and Max was just a baby?" She whispered. A rush of nostalgia went through Alec but he didn't say anything. "You used to hold him just like this until he fell asleep." Alec looked away in shame. It'd been painful remembering Max and Alec felt it would be easier to move on if he left the past behind him. But as he held Magnus in his arms, it was all rushing back to him and he'd never miss Max so much as he did right now. Alec rested his head on Isabelle's shoulder so that she wouldn't see the tears in his eyes.

"I'm sorry for shouting earlier." He said softly.

"It's not your fault." Isabelle said wrapping her arm around here brother's shoulder. "It's been a long day, let's get Maggie in bed and then maybe we can look around his study to see if there's anyone we can contact for help." She reassured. Alec smiled.

"Sounds like an idea." Alec stood up carefully and went into the bedroom where a dark polished wooden crib stood beside the bed. He laid down Magnus on the soft covered mattress and pulled up a blue blanket to his neck.

"He's sooo cute!" Isabelle squealed lightly rubbing his baby cheeks. Alec laughed.

"Let's go, before you wake him up." Alec said leading his sister out of the room and turned the lights off on his way out. He led his sister to the study then frowned and Isabelle crossed her arms over her chest.

"Looks like we got our work cut out for us." She said staring at the messy room. Books and paper were scattered along the desk and on the floor. There were also jars of unknown substance resting along the bookshelves that had thick coatings of dust. "Do you know if he kept a catalog of names, people he worked with, maybe other warlocks?" She asked walking over to his desk and picking a few loose papers. Alec winced and ran a hand through his hair.

"I didn't ask, I usually just sit on the couch and wait until he's done." Isabelle sighed theoretically.

"Let's get looking." She said and the two began to rifle around the room.

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**Another chapter complete! I hope you all enjoyed it and please review! **


	4. Chapter 4

**Thank you guys for the reviews! I enjoyed them. I'm sorry for the delay but it's here now, I hope you guys like it.**

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Chapter 4

**Suspicion**

Jace, Clary and Simon sat in one of the wooden booths at Taki's. Clary was swirling her smoothie around with her straw and Jace, who was sitting next to her, was cutting vigorously into his bloody stake and shoving a piece into his mouth. Simon took a sip of his tall glass of animal blood and licked his lips deliciously.

"I don't like it." Jace finally spoke.

"Don't like what?" Simon asked setting the glass down.

"Whatever Alec and Isabelle are doing at Magnus' place. It's been three days since Isabelle left; not counting the time she came back to grab few of her belongings and then left again. I've called and texted about a hundred times, and no one's answered me! What could they possibly be doing?" He demanded slamming his fist against the table.

"I think you're over reacting, it's probably just relationship problems." Clary said and Simon nodded in agreement. Jace didn't seem reassured, if anything, he looked more annoyed.

"If they were having relationship problems, Alec wouldn't even be in the same room with Magnus. Even I know that." Jace snorted. Simon looked down at his drink remembering the time he went to the Ironworks. He remembered approaching the table and Clary telling him that Magnus and Alec might be fighting, but he didn't have to be told that, the tension was clearly in the atmosphere. Then Alec went about Magnus not telling him about his past and stalked away from the table.

Simon shook his head and saw Clary looking at him and she raised her eyebrows probably thinking of the same thing. Clary looked at Jace.

"Would it make you feel better if we checked it out?" Her words were no sooner spoken when Jace slid out of the booth.

"Yes, now hurry up and finish." He said impatiently, pulling out what looked like money from his pocket and laid it on the table. Clary and Simon exchanged side glances then chugged down their drinks and followed Jace out of the restaurant.

The taxi pulled up on Magnus's street the three huddled out of the car. It was bad enough that Jace had long legs, but as he power walked down the side walk, Clary was practically running just to stay close behind him. Simon slowed, falling in steps with Clary, making Jace lead the way.

"I wonder what's gotten into him." He said quietly. Clary shrugged.

"Beats me. But he was pacing around him room since yesterday last night. I tried to calm him down, but he wouldn't listen to me. He kept saying he felt something was wrong through his parabati mark." They reached the red brick house and Jace rang the buzzer once, twice and a third time before a familiar voice came.

"Alright jezz, who is it?" Isabelle demanded.  
"It's me!" Jace called back. "Let me in." He said banging on the door.

"Oh…err…." There was a long pause and Jace crossed his arms over his chest and stomped his foot impatiently on the ground. At last, the door clicked open and Jace marched his way up stairs, Clary and Simon on his heel. At the top, Isabelle was waiting for him, her arms clasp behind her back, her hair up in a half ponytail held by a jade pin. She was wearing a black laced blouse with the wide neck with one side hanging off her shoulders relieving a black strap from her bra. She was wearing a floor length black skirt with purple flower patterns spread all around the material and sandals. Her eyes fell on Clary and Simon and she scowled.

"What are they doing here?" She exclaimed pointing a finger in their direction.

"Nice to see you too." Simon said.

"Whatever" Isabelle turned around and opened the door. "Alec is not going to be happy with this." She said to no one in particular.

"Isabelle, what's going on that you're not telling me?" Jace asked. He asked following her in the flat.

The interior was a creole type of style. The walls and ceilings were maroon colored in an elegant red hue shade. There was a camel back sofa in the center of two eighteenth century chairs all facing an elegant fire mantel that was currently closed off. It wasn't the interior that made Jace gap, but rather the playpen laid out in the center of the living room. Alec was kneeling next to a baby that was crawling all fours playing with a soft blue ball, almost like a kitten. He was wearing the usual faded jeans and a plain navy blue shirt.

"Okay, I know you and Magnus are serious, but I didn't think you were _that_ serious." Jace said, pointing to the baby, a look of disbelief on his face. Alec turned bright red in either anger or embarrassment but he didn't have time to protest when Clary came from behind Jace and saw the baby.

"Ohmygawd!" She exclaimed. Clary dashed forward and placed her hands on her knees looking down at the baby. "He is soo adorable, can I hold him?" She asked. A look of distress crossed Alec's face.

"Uh, wait-" But she was already picking him up in her arms and placing him on her hip. When the baby didn't protest, Alec let his hands fall to his side and he rose to his feet.

"Where is Magnus anyway?" Simon asked, coming to stand next to Clary. He reached out and tried to touch the baby but he cringed back, as if he were a scary monster. Simon frowned, dropping his hand in disappointment.

"That is Magnus." Isabelle said slowly. Jace, Clary, and Simon shared equally shocked expressions.

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**I know it was a little short, but I hope you liked it. Please review and let me know how it was. **


	5. Chapter 5

**Thank you so much for the reviews! And I'm sorry for the wait! I can assure you, i'm not giving up on this story! not ever! :D**

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Chapter 5

**Help?**

"WHAT?!" They all said in unison.

"How, what happened?" Clary asked.

"We're thinking a spell went wrong. We found someone that may be able to help us. Her name is Catarina Loss. She's another warlock like Magnus. She's meeting us today." Isabelle said then looked towards the clock that hung on the wall. "Actually now." With a shrug, she walked over to the sofa and sat down. Alec watched as Magnus stuck his fingers in his mouth and he looked from Clary to Simon to Jace and then back with wide curious eyes.

"Well, now that you mentioned it, he does look a lot like Magnus." Simon said. "His skin is the same caramel tone." He continued touching Magnus' arm in which the baby responded by jerking his arm away with a slight whimper.

"Your hands are probably cold Simon." Clary said apologetically. Simon folded his hands behind his back.

"Ha, you can't really tell if it's truly him when there's not a single hair on his_ widdle_ head." Jace teased though he'd found a few strands of hair on Magnus's head and began to twirl it between his fingers. Just then, Magnus began to cry and he began to kick his little feet and reach for Alec. Clary was a little more than startled that she almost dropped him. Alec shoved Simon and Jace aside and took him from Clary's arm. Magnus rested his head on Alec's shoulder and sniffled giving the three of them pouted looks.

"Wow, he has some crazy attachment issues." Jace said, amazed that Magnus had stopped crying. Magnus turned his head away.

"He can understand you, he just can't respond." Alec said flatly. "In the way he'd like to." He added and gently placed Magnus back on the floor, his arms cramping.

"Really?" Jace crouched next to Magnus and grinned. "So Magnus? What's it like being the size of your brain?" Magnus cried and huddled closer to Alec as if to hide from the blond boy.

"Jace, that's enough." Alec hissed.

"So how long has he been like this?" Clary asked turning to Isabelle who had her long legs stretched out along the cushion.

"A few days. Alec hopes she can change him back." As if the universe was responding, the sound the buzzer sounded the room.

"That's got to be her." Alec said sounding relieved and he began to get up when Clary offered to let her in. She opened the door to Magnus' apartment and suddenly her body tensed. Alec looked at Jace and his_ parabatai_ joined Clary at the door.

"Are you just going to stare or are going to let her in?" Alec heard Jace ask to Clary. She shook her head and stepped aside. Just then, a woman dressed in scrubs, as if she'd just come from work, stepping through the door. She had snow white shoulder length hair and blue skin, dark blue skin. Upon seeing Catarina, Magnus darted forward on all fours towards her. Catarina gasped aloud, a look of pure awe on her face and she bent down and picked him up in her arms.

"Magnus! Is that you? You're so adorable!" She said nuzzling her nose against his and he made a high pitch laugh. "What did you do huh?" She scolding kindly, bouncing lightly on the soles on her feet. "I don't see anything wrong with him, so you're probably right. He was most likely working on a spell." Catarina diagnosed. "I've seen this before. A common error in all warlocks that have nothing better to do in their life then mix up spells." She said to Alec.

"You came all the way just to tell us that? Even we could have figured that out!" Jace said throwing his hands up in the air. Alec shot Jace a warning look.

"Can you change him back?" He asked worriedly. She winced.

"It wouldn't be too difficult on his body and mind. Right now, he's adjusting to being a toddler and if I change that, it'll damage his brain, because it'll have to readjust." She shook her head. "Just let the spell wear off. The baby years tend to last the longest, ranging from two to four weeks, depending on the warlock and what spell he was working on. But after that, he should grow ascendingly fast. He should be back to normal in about two to three months." A look of despair and disappointment crossed Alec's face.

"That's a long time." He said.

"Not when you're having fun." She said. "Is this really all you have for Magnus?" she asked nodding towards the playpen. Alec nodded.

"We didn't know what to get him." Isabelle responded for Alec. Catarina shook her head in dismay.

"First, babies need a lot more room than this. They also need a lot more toys, they need letter boxes so they can learn words. Oh my, this won't do. Um, do you have a TV anywhere?" She asked walking around the flat.

"Yeah, it's in the den. Why?" Alec said showing her the den. The floor was carpeted in a beige color and the curtains were closed shutting out the afternoon light. There two chairs in the den and three bean bags placed around the center of the room. There was a big flat screen TV hanging on the wall that was currently off.

"This is a good place for him to play. Also, watch some shows with him. It'll help him learn- well relearn everything." She nodded and handed Magnus back to Alec. "Okay, I mostly do healing, but let's see if I can't do a little furniture moving." She winked. With a flick of her wrist, she removed the playpen from the common room and magiced it to the den. She grinned and with a snap of her fingers, a pile of toys appeared around the room. "There, that should keep him busy for a while." She said. "Alright Magnus, you be good!" She squealed inching his cheeks.

"Wait, what do I do?" Alec asked.

"Alec, what do babies do best?" She didn't give him time to answer. "Play. You play with him."

"Play? But-"

"I know you were raised in a Shadowhunter life, but this is different. He's not just going to sit nilly-willy on the floor and be good. No, he's a baby, he's a curious, flamboyant baby. He'll touch and break everything in his wake. He'll want to eat and taste everything because that's how they learn."

"Can't you take care of him?" Jace asked. Catarina raised an eyebrow at him.

"Do I look like a nanny to you? No, and as much as I'd love to, I have work. Besides, you guys are all capable of looking after him yourself." Jace snorted.

"Alec is last person to take care of a baby." Alec shot him a glare.

"I'll look after him if you want?" Clary offered. "I wasn't raised as a Shadowhunter so I know pretty much about taking care of babies."

"Yeah, me too. I can help." Simon jumped in.

"See Alec, your fine." She smiled reassuringly. "Call me if anything goes wrong." She said and walked out of the apartment.

"Two to three months huh?" Isabelle asked placing both hands on her hip, though it was more of a statement.

"Yup," Jace said and they all turned to look at baby Magnus in Alec's arm knowing it was going to be a long two months. Magnus looked back at them and laughed innocently, as if it were funny to him.

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**Yeah! now its SHENANIGINS TIME FROM HERE ON AFTER! Baby Magnus will be bold, daring, creative and chaotic! Will Alec be able to handle the struggle? Please REVIEW and let me know how it was! **


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